<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Feed
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Atom.php 18951 2009-11-12 16:26:19Z alexander $
 */


/**
 * @see Zend_Feed_Entry_Abstract
 */
require_once 'Zend/Feed/Entry/Abstract.php';


/**
 * Concrete class for working with Atom entries.
 *
 * @category   Zend
 * @package    Zend_Feed
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Feed_Entry_Atom extends Zend_Feed_Entry_Abstract
{
	/**
	 * Content-Type
	 */
	const CONTENT_TYPE = 'application/atom+xml';

	/**
	 * Root XML element for Atom entries.
	 *
	 * @var string
	 */
	protected $_rootElement = 'entry';

	/**
	 * Root namespace for Atom entries.
	 *
	 * @var string
	 */
	protected $_rootNamespace = 'atom';


	/**
	 * Delete an atom entry.
	 *
	 * Delete tries to delete this entry from its feed. If the entry
	 * does not contain a link rel="edit", we throw an error (either
	 * the entry does not yet exist or this is not an editable
	 * feed). If we have a link rel="edit", we do the empty-body
	 * HTTP DELETE to that URI and check for a response of 2xx.
	 * Usually the response would be 204 No Content, but the Atom
	 * Publishing Protocol permits it to be 200 OK.
	 *
	 * @return void
	 * @throws Zend_Feed_Exception
	 */
	public function delete()
	{
		// Look for link rel="edit" in the entry object.
		$deleteUri = $this->link('edit');
		if (!$deleteUri) {
			/**
			 * @see Zend_Feed_Exception
			 */
			require_once 'Zend/Feed/Exception.php';
			throw new Zend_Feed_Exception('Cannot delete entry; no link rel="edit" is present.');
		}

		// DELETE
		$client = Zend_Feed::getHttpClient();
		do {
			$client->setUri($deleteUri);
			if (Zend_Feed::getHttpMethodOverride()) {
				$client->setHeader('X-HTTP-Method-Override', 'DELETE');
				$response = $client->request('POST');
			} else {
				$response = $client->request('DELETE');
			}
			$httpStatus = $response->getStatus();
			switch ((int) $httpStatus / 100) {
				// Success
				case 2:
					return true;
					// Redirect
				case 3:
					$deleteUri = $response->getHeader('Location');
					continue;
					// Error
				default:
					/**
					 * @see Zend_Feed_Exception
					 */
					require_once 'Zend/Feed/Exception.php';
					throw new Zend_Feed_Exception("Expected response code 2xx, got $httpStatus");
			}
		} while (true);
	}


	/**
	 * Save a new or updated Atom entry.
	 *
	 * Save is used to either create new entries or to save changes to
	 * existing ones. If we have a link rel="edit", we are changing
	 * an existing entry. In this case we re-serialize the entry and
	 * PUT it to the edit URI, checking for a 200 OK result.
	 *
	 * For posting new entries, you must specify the $postUri
	 * parameter to save() to tell the object where to post itself.
	 * We use $postUri and POST the serialized entry there, checking
	 * for a 201 Created response. If the insert is successful, we
	 * then parse the response from the POST to get any values that
	 * the server has generated: an id, an updated time, and its new
	 * link rel="edit".
	 *
	 * @param  string $postUri Location to POST for creating new entries.
	 * @return void
	 * @throws Zend_Feed_Exception
	 */
	public function save($postUri = null)
	{
		if ($this->id()) {
			// If id is set, look for link rel="edit" in the
			// entry object and PUT.
			$editUri = $this->link('edit');
			if (!$editUri) {
				/**
				 * @see Zend_Feed_Exception
				 */
				require_once 'Zend/Feed/Exception.php';
				throw new Zend_Feed_Exception('Cannot edit entry; no link rel="edit" is present.');
			}

			$client = Zend_Feed::getHttpClient();
			$client->setUri($editUri);
			if (Zend_Feed::getHttpMethodOverride()) {
				$client->setHeaders(array('X-HTTP-Method-Override: PUT',
                    'Content-Type: ' . self::CONTENT_TYPE));
				$client->setRawData($this->saveXML());
				$response = $client->request('POST');
			} else {
				$client->setHeaders('Content-Type', self::CONTENT_TYPE);
				$client->setRawData($this->saveXML());
				$response = $client->request('PUT');
			}
			if ($response->getStatus() !== 200) {
				/**
				 * @see Zend_Feed_Exception
				 */
				require_once 'Zend/Feed/Exception.php';
				throw new Zend_Feed_Exception('Expected response code 200, got ' . $response->getStatus());
			}
		} else {
			if ($postUri === null) {
				/**
				 * @see Zend_Feed_Exception
				 */
				require_once 'Zend/Feed/Exception.php';
				throw new Zend_Feed_Exception('PostURI must be specified to save new entries.');
			}
			$client = Zend_Feed::getHttpClient();
			$client->setUri($postUri);
			$client->setHeaders('Content-Type', self::CONTENT_TYPE);
			$client->setRawData($this->saveXML());
			$response = $client->request('POST');

			if ($response->getStatus() !== 201) {
				/**
				 * @see Zend_Feed_Exception
				 */
				require_once 'Zend/Feed/Exception.php';
				throw new Zend_Feed_Exception('Expected response code 201, got '
				. $response->getStatus());
			}
		}

		// Update internal properties using $client->responseBody;
		@ini_set('track_errors', 1);
		$newEntry = new DOMDocument;
		$status = @$newEntry->loadXML($response->getBody());
		@ini_restore('track_errors');

		if (!$status) {
			// prevent the class to generate an undefined variable notice (ZF-2590)
			if (!isset($php_errormsg)) {
				if (function_exists('xdebug_is_enabled')) {
					$php_errormsg = '(error message not available, when XDebug is running)';
				} else {
					$php_errormsg = '(error message not available)';
				}
			}

			/**
			 * @see Zend_Feed_Exception
			 */
			require_once 'Zend/Feed/Exception.php';
			throw new Zend_Feed_Exception('XML cannot be parsed: ' . $php_errormsg);
		}

		$newEntry = $newEntry->getElementsByTagName($this->_rootElement)->item(0);
		if (!$newEntry) {
			/**
			 * @see Zend_Feed_Exception
			 */
			require_once 'Zend/Feed/Exception.php';
			throw new Zend_Feed_Exception('No root <feed> element found in server response:'
			. "\n\n" . $client->responseBody);
		}

		if ($this->_element->parentNode) {
			$oldElement = $this->_element;
			$this->_element = $oldElement->ownerDocument->importNode($newEntry, true);
			$oldElement->parentNode->replaceChild($this->_element, $oldElement);
		} else {
			$this->_element = $newEntry;
		}
	}


	/**
	 * Easy access to <link> tags keyed by "rel" attributes.
	 *
	 * If $elt->link() is called with no arguments, we will attempt to
	 * return the value of the <link> tag(s) like all other
	 * method-syntax attribute access. If an argument is passed to
	 * link(), however, then we will return the "href" value of the
	 * first <link> tag that has a "rel" attribute matching $rel:
	 *
	 * $elt->link(): returns the value of the link tag.
	 * $elt->link('self'): returns the href from the first <link rel="self"> in the entry.
	 *
	 * @param  string $rel The "rel" attribute to look for.
	 * @return mixed
	 */
	public function link($rel = null)
	{
		if ($rel === null) {
			return parent::__call('link', null);
		}

		// index link tags by their "rel" attribute.
		$links = parent::__get('link');
		if (!is_array($links)) {
			if ($links instanceof Zend_Feed_Element) {
				$links = array($links);
			} else {
				return $links;
			}
		}

		foreach ($links as $link) {
			if (empty($link['rel'])) {
				$link['rel'] = 'alternate'; // see Atom 1.0 spec
			}
			if ($rel == $link['rel']) {
				return $link['href'];
			}
		}

		return null;
	}

}
